Momentum of electron is 1 kg m/s. What is kinetic energy of the electron?
The rest mass energy is insignificant compared to that enormous momentum/energy. The electron might as well be a photon. E = pc It’s probably worth noting that this kind of energy is so far beyond what we understand that we really have no right to assume we can extrapolate physics as we know it to that level. So my answer is probably not much better than the one you would have gotten in 1900 (or down below).
